Maria Ignez Braghiroli, MD
Activating, hotspot mutations in the NRAS gene occur in a small subset of patients with metastatic colorectal cancer (mCRC). These mutations are now being identified in routine clinical practice by extended RAS genotyping.
Maria Ignez Braghiroli, MD, and her colleagues recently published the results of a study in which the investigators sought to identify the clinical and molecular characteristics of patients with NRAS-mutated mCRC. These findings were presented at the 2016 ESMO Congress.
The results demonstrated that NRAS
-mutant mCRC is an aggressive subset of CRC, with worse overall survival rates than that of patients with RAS
wild-type tumors or KRAS
The researchers also found that NRAS mutations define a clinically distinct subgroup of mCRC with increased left-sided colon primary tumors.
In an interview with OncLive
, Braghiroli, medical oncologist, Instituto do Câncer do Estado de São Paulo, discusses the current treatment paradigm for these patients and the need for more individualized treatment approaches in this setting.
OncLive: Can you tell us about clinical characteristics of patients with mCRC harboring NRAS mutations?
: We've been trying to molecularly characterize the type of tumors, and possibly try to individualize treatment. What we did is we selected all the colorectal cancer patients that were found to have NRAS
mutations from 2008 to 2015 that were treated at Memorial Sloan Kettering. We found a total of 87 patients, and we had to exclude 3 patients because they had concurrent KRAS
mutations and we wanted the patients with NRAS
mutations only. Then we compared this population in terms of clinical characteristics, molecular characteristics, and outcomes to treatment in the population with KRAS
mutations and all RAS wild type tumors.
You excluded patients with KRAS mutations. How would that have affected the results?
We don't really know, and that's why we excluded only 3 that had both the NRAS
mutations. That's why we didn't include them in the NRAS
-mutated patients only.
What would you say the current treatment paradigm is for NRAS-mutant metastatic colorectal cancer?
Basically, we know that anti-EGFR medications don't work for KRAS
-mutant patients and also the NRAS
-mutant patients. These are the smaller proportion of patients with colorectal cancer, around 3% to 7%. That's why we don't really know what happens to this specific subtype of RAS
mutation patients, and that is why we were looking into it.
How much would you say mutation status affects the individual treatment of patients with colorectal cancer?
Specifically for the RAS
-mutated patients, we know that they do not respond to the anti-EGFR mutations. In general, we know that maybe BRAF
-mutated patients have a much worse prognosis, and the studies currently focused on BRAF inhibitors or MEK inhibitors, or a combination of BRAF, MEK, and anti-EGFR inhibitors in these patients. That is actually being performed at Memorial Sloan Kettering also. A small subtype of patients actually have an amplification of HER2, for example, and they might benefit from anti-HER2 treatment.